Border control staff at Heathrow Airport have been instructed to drop checks targeting drugs and arms smugglers in order to keep queues down.

Frontline officials and immigration staff unions highlighted the pressures of staff shortages at major airports in the run-up to this year’s Olympic Games in London.

Passengers at Heathrow are facing fewer checks as staff battle to control queues (Getty)

A senior officer told the Observer that the UK’s busiest airport was becoming dangerously open for those who were looking to bring contraband into the country.

The anonymous immigration worker told the newspaper Heathrow effectively had ‘no border controls’ when it came to items such as drugs and illicit weapons.

‘We have actually ceased doing [anti-smuggling operations] at the moment, even though they won’t say they have. Word has already got around to criminal enterprises,’ the source explained.

In response to the accusations, a Home Office spokesman said: ‘We are committed to maintaining border security. By deploying our staff flexibly we are continuing to target drugs and illegal weapons while carrying out our immigration work as rigorously and efficiently as possible.’

The Public and Commercial Services Union, which represents border control staff, has also warned that moving staff to passport control in an effort to cut waiting times has reduced the ability for workers to carry out extra baggage checks and question suspect passengers.

All eyes are on home secretary Theresa May in the run-up to the Olympics, when the world’s focus will be on the UK’s ability to handle an international event of such stature.